The risk of Lyme disease in the US 'is expanding in all directions'

Borrelia
burgerdorferi bacteria as seen with a scanning electron
microscope.Claudia
Molins/CDC

NEW YORK (AP) — The geographic areas where Lyme disease is a
bigger danger have grown dramatically, according to a new
government study published Wednesday.

US cases remain concentrated in the Northeast and upper Midwest.
But now more areas in those regions are considered high risk.

"The risk is expanding, in all directions," said the lead author,
Kiersten Kugeler of the Centers for Disease Control (CDC).

There are now 260 counties where the number of Lyme
disease cases is at least twice what's expected, given the size
of each county's population. That's up from 130 a decade earlier,
the report shows.

Lyme disease is most common in wooded suburban and far suburban
counties. Scientists aren't sure why high-risk areas are
expanding, but it likely has something to do with development and
other changes that cause animals (e.g. deer, mice, and squirrels)
and ticks that carry the bacteria to move, Kugeler said.

Overall, 17 states have high-risk counties. The entire state of
Connecticut, where the illness was first identified in 1975, has
been high-risk for decades. Now, high-risk zones encompass nearly
all of Massachusetts and New Hampshire and more than half of
Maine and Vermont.

Other states that saw expansion of high-risk areas include
Virginia, Pennsylvania and New York along the Eastern seaboard,
and Iowa, Michigan and Minnesota in the Midwest.

Here's an animation showing how the problem has grown:

The disease is transmitted through the bites of infected deer
ticks, which can be about the size of a poppy seed.

Symptoms include a fever, headache and fatigue and sometimes a
telltale rash that looks like a bull's-eye on the tick bite.
Those infected can develop severe, rheumatoid arthritis-like
joint and muscle pain. Fatigue and neurological disorders — such
as numbness, tingling, weakness, and cognitive impairment — can
set in too.

Most people recover after a course of antibiotics. If left
untreated, infections can lead to brain inflammation or heart
problems. At least a handful of such cases have proven fatal.

About 30,000 US cases are reported each year, but experts
say there actually are as many as 10 times more. Up to 440,000
cases might have occured in 2008, for example.

Nymph
blacklegged ticks (right) are tiny compared to adults (left) but
are the most common vectors for Lyme disease.Getty Images

Some counties have dropped off the high-risk list, including
those in Virginia, Georgia, Missouri and North Carolina where
significant clusters were reported in the 1990s. Scientists now
think those were a different condition caused by a different
tick's bite, Kugeler said.

Some experts argue a vaccine could be effective in preventing
cases to begin with.

SmithKline Beecham (now GlaxoSmithKline) developed a vaccine for
Lyme disease, called LYMErix, and started selling doses in 1998.
It was 80 percent effective after two booster shots.

But several forces conspired to lead the manufacturer to
stop selling it in 2002 — not the least of which were
outspoken antivaccine groups and their lawyers. Plaintiffs in one
case claimed the vaccine caused Lyme disease-like symptoms in
some people. GlaxoSmithKline eventually settled out of court, but an official follow-up
study found nothing abnormal
about the vaccine.

Another manufacturer had developed a second promising vaccine at
the time, but it never pursued licensing following their
competitor's lawsuits. At least one new vaccine is in
development, one expert recently told Business Insider, but it's
not yet ready for a public debut.

"Primary prevention is something where we're clearly losing the
battle on," Dr. Paul Mead, chief of epidemiology and surveillance
for the CDC's Lyme disease program, told Business Insider in
June. "A safe and effective vaccine could help us turn the tide."